Knightstale04

Driving me crazy gas fumes!I have heavy gasoline fumes coming into the cabin of my 2012 C250 Coupe whenever I exit the freeway after traveling distances. I recently had my takata airbags replaced at the Mercedes dealership in Walnut Creek and had them also check out what was causing the gasoline fumes. They did a full diagnostic, but could not explain why the gas was getting into my oil. The car runs well, and passed all the Mercedes diagnostic tests with no problems. I have researched every piece of information I can find about these symptoms, and the 2 potential solutions are replacing the PCV valve (discontinued part?) which I am unable to locate from any parts store, and the crankcase vent pipe/valve which I am having a difficult time identifying.

I was having an intermittent CEL, a failed thermostat code. I thought it could be causing the car to run rich? Thinking the CPU would send additional gas to the cold engine with the thermostat stuck open? I replaced the thermostat and still have gas fumes. That procedure has caused a new issue with the air intake pipe not seating all the way onto the Turbo collar. There is a plastic lip inside the air intake pipe that is blocking it from sliding into position. The connection is in a very difficult spot for applying leverage. Suggestions?

Anyway, there must be someone out there that has had similar symptoms who knows why gas is getting into my oil, with no performance loss or service error codes being reported?

Please advise? Thank you sincerely if you can help me!

Ahakim24

im having the same issue with my c350... not sure what to do as of right now other than change the oil asap. if I find any solutions ill lyk and id hope you do the same for me.

Knightstale04

I am sure we are not the only C250 owners with this same issue, and the cabin fumes are brutal at times. With gas fumes there is a serious safety issue, so when I find the solution to this problem I will post it immediately. The super frustrating part of trying to figure this out, is that I had it checked out at the Walnut Creek Mercedes Benz service department. I paid for the disgnostic service because gas fumes are dangerous, and all they could tell me was there is a gas smell lin the oil, but nothing related to a solution or cause. They thought it was because the oil had not been changed recently, but I change the oil more often than is recommended. When a major authorized Mercedes service center cannot solve the issue, where else can you go? Thank you sincrely for responding, the only response I have received so far.

ezshift5

I own the same car. I run lucky, I reckon (Zero issues since 2014 purchase...... But I do have access to a great dealership).

If I were you I'd give them a call. You'er not happy. You recognize the serious safety issue............ .

The Service Director is Jason Downing. I can't find his direct number - but the dealer line is (916) 567-5100. Speak to Jason. Use my name if you like (Fred Fletcher - purchased C250 coupe August 31, 2014).

Knightstale04

Thank you so much for recommending somewhere with quality workmanship. Competent mechanics that can be trusted are very difficult to find. I love this car, it is by far the nicest automobile I have ever owned. Love the engineering, the smoothness and the look! That is why it is so frustrating to have this issue. The car is running perfectly, no warning lights, no performance loss, just major gas fumes in the cabin and engine bay. I would make the road trip to El Dorado Hills if I could, but part of the reason I am experiencing problems with my car is the distance I travel beack and forth to work everyday. Currently the round trip is 100 miles. I have a 2013 Mini Clunman also, just paid $4000 to get that back on the road. What a contrast in the drive of the two vehicles, the Mercedes has spoiled me! Thank you so much for taking the time to send me somewhere you trust could fix this! El Dorado Hills would be tough to drop off the car and make it back home to Pittsburg. Thank you!